A person of ordinary skill in the art will readily understand that a gas lighter generally includes a gas reservoir that contains a liquefied petroleum gas, a valve on the reservoir that allows the fuel to be emitted from the reservoir with a determined flow, a system of opening and closing of the valve as well as an ignition system. A lighter known in the art typically includes a pyrophoric stone flint that cooperates with a spark wheel to produce sparks that light the gas emitted from the reservoir. The spark wheel is typically assembled on an axis between two cheeks attached to the axis, and both are generally protected by a hood. The spark wheel typically has a cylindrical shape and the cheeks have a shape of a disc having an external diameter appreciably higher than that of the spark wheel. The periphery of the cheeks typically includes asperities making the surface rough. Therefore, a user can easily actuate the spark wheel with a finger, for the finger does not slip on the cheeks.
A person of ordinary skill in the art will also readily understand that for a gas lighter having the features described above, when the spark wheel, in contact with the stone, is put in rotation by the intermediary of the cheeks and the finger of the user, a shower of sparks is created and followed, by the action of this same finger on the fork of opening of the gas (referred to in the art as the “roll and press” system), of a release of a quantity of gas. The shower of sparks ignites gas then by producing a flame above the hood. A typical lighter as described above therefore only requires a positive action from the user to produce and maintain a flame and requires only one tangential movement starting the rotation of the spark wheel in a first step, and then ending in an action on the gas opening fork to produce a flame. There have been efforts to increase the difficulty of using such lighters so that children less than five years old cannot produce flames using the lighters as described above. For example, WO 97/01734 describes a lighter that uses smooth cheeks to make it more difficult for children to rotate the cheeks. Similarly, U.S. Pat. No. 5,096,414 (“the '414 patent”), is directed to a lighter that includes a striker wheel 6 disposed between two plates 7, 8 that have a greater diameter and are freely rotatable with respect to the striker wheel 6. In the '414 patent, a user actuates the striker wheel 6 by friction thanks to the deformation 11 of the pulp of the thumb 10 of the user, i.e., children are not able to similarly actuate the lighter because the pulp of their fingers is not sufficiently thick.
Other U.S. patents disclose childproof mechanisms to make it more difficult for children to use them. For example, U.S. Pat. No. 5,490,773 is directed to a “Pocket Lighter” and includes features directed to a spark wheel's rotary shaft that is capable of being disposed in first and second positions in the housing (see FIG. 1, reference numerals 12 and 13) where the first position shown in FIG. 8 causes the spark wheel to be blocked from turning and the second position shown in FIG. 9 allows the spark wheel to be unblocked to allow it to strike the flint to cause the required sparking. In addition, U.S. Pat. No. 5,971,748, is directed to a “Gas Safety Lighter Comprising a Pyrophoric Flint and Spark Wheel Ignition System” and includes features related to an axis of a valve lever mounted movably with respect to the body of the lighter between an active position (shown in FIG. 8) permitting the operation of the valve mounted on the reservoir and a rest position (shown in FIG. 5) in which action on the lever does not permit operation of the valve.
The lighters described above and in related prior art references require an additional device to inhibit access to the cheeks of the spark wheel, they render the driving of the spark wheel to be more difficult, they block the movement of the gas opening fork, and the parts of the ignition system and gas opening system are usually visible by and accessible by children. These lighters typically have a complex structure that lead to high manufacturing costs. Moreover, the use of some of these lighters is difficult or complicated even for adults.
At least for these reasons, there is a need for a lighter that is easily usable by an adult, but more difficult to use by a child such as a lighter having a pivoting ignition subset as described in more detail below.